WO2023105859A1

WO2023105859A1 - Rotor and rotating electric machine

Info

Publication number: WO2023105859A1
Application number: PCT/JP2022/032322
Authority: WO
Inventors: 貴生義本
Original assignee: 株式会社デンソー
Priority date: 2021-12-09
Filing date: 2022-08-29
Publication date: 2023-06-15
Also published as: JP2023085938A; CN118339744A; DE112022005880T5; US20240333053A1

Abstract

A rotor (20) comprises a permanent magnet (23) and a rotor core (22) including a plurality of core sheets (30). A plurality of magnetic poles (26) of the rotor each include the permanent magnet and an outside core portion (25). The outside core portion is constituted by laminating the outside core portions (34a, 34b) of the individual core sheets. The outside core portion is supported with respect to the periphery region of the rotor core by bridge portions (22d, 22e, 22c) at a plurality of sites including a bridge portion positioned on at least one side of a pair of outside end portions (24c) of a magnet housing hole in the radial direction. In the outside core portion, the outside core portion (34b) is at least mixed that is supported by one bridge piece (32c) of the core sheets constituting the bridge portion (22e) at the outside end portion in the radial direction on one side. When the plurality of core sheets are formed in a laminated state, the support form of the outside core portion by the bridge portions at the plurality of sites is established.

Description

Rotor and rotary electric machine

Cross-reference to related applications

This application is based on Japanese Application No. 2021-200266 filed on December 9, 2021, and the contents thereof are incorporated herein.

The present disclosure relates to an embedded magnet rotor and rotating electric machine.

In a rotating electrical machine, an embedded magnet type (so-called IPM type) rotor is well known in which permanent magnets are embedded in radially inner positions of the rotor core. The embedded magnet type rotor is configured to obtain reluctance torque at an outer core portion located radially outside the permanent magnets, in addition to magnet torque from the permanent magnets.

In the embedded magnet type rotor, for example, as shown in Patent Document 1, the permanent magnets are embedded in a folded shape convex radially inward, such as a V-shape or a U-shape when viewed in the axial direction. When the folded shape of the permanent magnet is deepened radially inward, the outer core portion can be made large. That is, the larger the outer core portion is, the more reluctance torque can be obtained, which can lead to higher torque of the rotary electric machine.

JP 2018-85779 A

The above embedded magnet type rotor requires the formation of magnet accommodation holes for accommodating permanent magnets in the rotor core. The outer core portion, which is provided so as to be surrounded by the magnet housing holes, is configured to be connected to the main body side of the rotor core at a narrow connecting portion called a bridge portion. The bridge portion is also the portion where some of the effective magnetic flux occurs as leakage. In order to reduce the leakage magnetic flux and thereby increase the torque of the rotary electric machine, it is desired to minimize the bridge portion or omit a part of the bridge portion.

On the other hand, however, the bridge portion is also a portion that supports the outer core portion with respect to the peripheral portion of the rotor core. Therefore, if the bridge portion is not appropriately minimized or omitted, the support rigidity of the outer core portion will be lowered, and there is an increased concern that the strength of the rotor, for example, the centrifugal force, will be lowered.

An object of the present disclosure is to provide a rotor and a rotating electric machine capable of reducing leakage magnetic flux while taking into account the strength of centrifugal force.
A rotor according to an aspect of the present disclosure includes a rotor core including a plurality of laminated core sheets and having a magnet housing hole having a folded shape convex radially inward; and permanent magnets embedded in the magnet housing holes of the rotor core. Prepare. The rotor includes a plurality of magnetic pole pieces. Each of the plurality of magnetic pole portions includes the permanent magnet positioned radially inside the rotor core, and an outer core portion which is a portion of the rotor core positioned radially outside the permanent magnet. The outer core portion of the rotor core is formed by stacking the outer core portions of the individual core sheets, and a bridge is positioned on at least one side of a pair of radially outer end portions of the folded magnet accommodating holes. It is supported with respect to the peripheral portion of the rotor core at a plurality of bridge portions including a portion. In the outer core portion of the rotor core, at least the outer core portion supported by one bridge piece of the core sheet forming the bridge portion of the one radially outer end portion is mixed, and a plurality of By stacking the core sheets, the outer core portion is supported by the plurality of bridge portions.

A rotating electric machine according to a further aspect of the present disclosure includes a rotor and a stator. The rotor includes a rotor core that includes a plurality of laminated core sheets and has a magnet housing hole that is convex radially inward and has a folded shape, and permanent magnets that are embedded in the magnet housing holes of the rotor core. The stator applies a rotating magnetic field to the rotor. A rotor of the rotating electric machine includes a plurality of magnetic pole portions. Each of the plurality of magnetic pole portions includes the permanent magnet positioned radially inside the rotor core, and an outer core portion which is a portion of the rotor core positioned radially outside the permanent magnet. The outer core portion of the rotor core is formed by stacking the outer core portions of the individual core sheets, and a bridge is positioned on at least one side of a pair of radially outer end portions of the folded magnet accommodating holes. It is supported with respect to the peripheral portion of the rotor core at a plurality of bridge portions including a portion. In the outer core portion of the rotor core, at least the outer core portion supported by one bridge piece of the core sheet forming the bridge portion of the one radially outer end portion is mixed, and a plurality of By stacking the core sheets, the outer core portion is supported by the plurality of bridge portions.

According to the rotor and rotating electric machine described above, the outer core portion surrounded by the magnet containing holes and the permanent magnets includes at least one of the pair of radially outer end portions of the magnet containing holes that are folded back with respect to the peripheral portion of the rotor core. It is supported by a plurality of bridge portions including the bridge portion located on the side. In each core sheet, when configuring one outer core portion, at least the outer core portion supported by one bridge piece constituting the bridge portion at one radially outer end portion is mixed. . When a plurality of core sheets are laminated to manufacture a rotor core, the outer core portion is supported by a plurality of bridge portions. Since the support rigidity of the outer core portion supported by the bridge portions at a plurality of locations is sufficiently high, the centrifugal force strength of the rotor can be ensured. On the other hand, by mixing the outer core portions supported by one bridge piece, the individual bridge pieces constituting the bridge portion that supports the outer core portion are appropriately thinned out. It is also possible to reduce leakage magnetic flux, which is a concern in each bridge portion.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description in conjunction with the accompanying drawings. The drawing is
FIG. 1 is a configuration diagram of a rotating electric machine having an embedded magnet type rotor in one embodiment, FIG. 2 is a plan view of the rotor in the same embodiment, 3(a) and 3(b) are plan views of core sheets used in the same embodiment, 4 is a cross-sectional view of the rotor shown in FIG. 2 taken along line 4-4, 5 is a cross-sectional view of the rotor shown in FIG. 2 taken along line 5-5, 6 is a cross-sectional view of the rotor shown in FIG. 2 taken along line 6-6, FIG. 7 is a configuration diagram of a rotating electrical machine including a rotor in the same embodiment, FIG. 8 is a configuration diagram of a rotating electrical machine including a rotor in Comparative Example 1; FIG. 9 is a configuration diagram of a rotating electrical machine including a rotor in Comparative Example 2; FIG. 10 is a comparison diagram of torque (cogging torque) corresponding to various shapes of permanent magnets. FIG. 11 is a comparison diagram of torque (torque ripple) corresponding to various shapes of permanent magnets, FIG. 12 is a comparison diagram of torque ripple rates corresponding to various shapes of the tapered portion; FIG. 13 is a comparison diagram of torque ripple rates corresponding to various shapes of the tapered portion; FIG. 14 is a configuration diagram of a rotating electrical machine of a modification in which the permanent magnet shapes of adjacent magnetic pole portions are different; FIG. 15 is a comparison diagram of cogging torque in the modification, FIG. 16 is a comparison diagram of the torque ripple rate in the modified example.

An embodiment of a rotor and a rotating electrical machine will be described below.
[Rotating electric machine M]
The rotary electric machine M of the present embodiment shown in FIG. 1 is configured by an embedded magnet brushless motor. The rotary electric machine M includes a substantially annular stator 10 and a substantially columnar rotor 20 rotatably arranged in a radially inner space of the stator 10 . Stator 10 imparts a rotating magnetic field to rotor 20 . The rotor 20 rotates by receiving a rotating magnetic field generated by the stator 10 .

[Stator 10]
The stator 10 has a substantially annular stator core 11 . The stator core 11 is made of a magnetic metal material. The stator core 11 is configured by laminating a plurality of electromagnetic steel sheets, for example. The stator core 11 extends radially inward and has twelve teeth 12 arranged at equal intervals in the circumferential direction in this embodiment. Each tooth 12 has the same shape. The tooth 12 has a substantially T-shaped radially inner end, which is a tip. Tip surfaces 12 a of the teeth 12 are arc-shaped following the outer peripheral surface of the rotor 20 . A winding 13 is wound around each of the 12 teeth 12 by concentrated winding. That is, the number of magnetic poles of the stator 10 is "12". The windings 13 are three-phase connected and function as U-phase, V-phase, and W-phase, respectively, as shown in FIG. When power is supplied to the windings 13 , a rotating magnetic field for rotating the rotor 20 is generated in the stator 10 . In such a stator 10 , the outer peripheral surface of stator core 11 is fixed to the inner peripheral surface of housing 14 .

[Rotor 20]
The rotor 20 includes a rotating shaft 21, a substantially cylindrical rotor core 22 in which the rotating shaft 21 is fitted and inserted in the center, and eight permanent magnets 23 embedded in radially inner positions of the rotor core 22 in this embodiment. It has That is, the number of magnetic poles of the rotor 20 is "8". The rotor 20 is rotatably arranged with respect to the stator 10 by supporting a rotating shaft 21 on a bearing (not shown) provided in the housing 14 .

[Rotor core 22]
As shown in FIG. 2, the rotor core 22 has magnet housing holes 24 for housing permanent magnets 23 therein. In this embodiment, eight magnet housing holes 24 are provided at equal intervals in the circumferential direction of the rotor core 22 . Each magnet housing hole 24 penetrates the rotor core 22 along the axial direction. Each magnet housing hole 24 has a substantially V-shaped folded shape protruding radially inward when viewed in the axial direction.

Each magnet housing hole 24 has a pair of linear portions 24a that are linear when viewed in the axial direction, and a bent portion 24b that connects radially inner ends of the pair of linear portions 24a. The pair of linear portions 24a gradually approach from the radially outer side to the inner side. Adjacent linear portions 24a in adjacent magnet housing holes 24 are arranged in parallel so as to be parallel to each other. Each linear portion 24a has its own radially outer end portion 24c located near the outer peripheral surface 22a of the rotor core 22, and is partially open to the outer peripheral surface 22a (see FIG. 4). The bent portion 24b is positioned near the shaft fitting insertion hole 22b in the central portion of the rotor core 22 into which the rotating shaft 21 is fitted. In other words, each magnet housing hole 24 has a substantially V-shaped folded shape that protrudes greatly from the radially outer side to the inner side.

Specifically, each magnet accommodation hole 24 of the present embodiment has a mixture of two types of hole structures, the magnet accommodation hole 24 of the first aspect A1 and the magnet accommodation hole 24 of the second aspect A2. The magnet housing holes 24 of the first and second modes A1 and A2 are provided alternately in the circumferential direction, and are provided alternately in the circumferential direction. In the magnet housing holes 24 of the first and second modes A1 and A2, first and second magnet through

holes

31 and 32 formed in a core sheet 30 (see FIG. 3), which will be described later, are arranged alternately in the axial direction. consists of The magnet housing holes 24 of the first and second aspects A1 and A2 look like different holes when viewed in the axial direction because the first and second magnet through

holes

31 and 32 are arranged in different order in the axial direction. has the same configuration. The detailed configuration of the magnet housing holes 24 of the first and second modes A1 and A2 will be described later.

[Permanent magnet 23 and outer core portion 25]
In this embodiment, the permanent magnet 23 is a bond magnet formed by molding and solidifying a magnetic material in which magnet powder is mixed with resin. That is, the magnet housing holes 24 of the rotor core 22 are molds for the permanent magnets 23 . When the magnet material is filled into the magnet housing holes 24 without gaps by injection molding, the permanent magnets 23 are formed by solidifying the magnet material in the magnet housing holes 24 . Therefore, the hole shape of the magnet housing hole 24 is the outer shape of the permanent magnet 23 . Samarium-iron-nitrogen (SmFeN)-based magnets, for example, are used as the magnet powder used for the permanent magnets 23 of the present embodiment, but other rare earth magnets and the like may also be used.

As shown in FIG. 2 , each permanent magnet 23 is formed directly in each magnet accommodation hole 24 , so that each permanent magnet 23 has a shape corresponding to each magnet accommodation hole 24 , which is convex radially inward when viewed in the axial direction. has a substantially V-shaped folded shape. Each permanent magnet 23 has a pair of straight portions 23a positioned within a pair of straight portions 24a of each magnet housing hole 24, and a pair of straight portions 23a positioned within a curved portion 24b of each magnet housing hole 24. It has a bent portion 23b that connects the inner ends. The pair of linear portions 23a gradually approach from the radially outer side to the inner side. Adjacent linear portions 23a of adjacent permanent magnets 23 are arranged in parallel to each other. A radially outer end portion of the straight portion 23a is located near the outer peripheral surface 22a of the rotor core 22 and partially exposed to the outer peripheral surface 22a (see FIG. 4). The bent portion 23b is located near the shaft fitting insertion hole 22b in the central portion of the rotor core 22 into which the rotating shaft 21 is fitted. That is, each permanent magnet 23 has a substantially V-shaped folded shape that protrudes greatly from the radially outer side to the inner side.

A portion of the rotor core 22 located inside the V-shaped folded permanent magnet 23 and radially outward of the permanent magnet 23 functions as an outer core portion 25 that faces the stator 10 and obtains reluctance torque. Eight outer core portions 25 are provided like the permanent magnets 23 . Each outer core portion 25 has a substantially triangular shape with one vertex directed toward the center portion of the rotor 20 when viewed in the axial direction. One magnetic pole portion 26 of the rotor 20 is composed of one permanent magnet 23 and one outer core portion 25 . The rotor 20 of this embodiment has eight magnetic pole portions 26 . In each magnetic pole portion 26 of the present embodiment, the curvature of the individual outer peripheral surface 26a is set larger than the curvature when the outer peripheral surface 22a of the rotor core 22 is a uniform circle. That is, the outer peripheral surface 22a of the rotor core 22 has a wavy shape that is slightly convex radially outward for each magnetic pole portion 26 .

As described above, each magnet housing hole 24 in which each permanent magnet 23 is provided has two types of magnet housing holes 24 of the first and second aspects A1 and A2, but the substantial hole structure is the same. Therefore, although the magnetic pole portions 26, that is, the permanent magnets 23 and the outer core portions 25 appear to have different shapes and arrangements when viewed in the axial direction, they have substantially the same configuration. Hereinafter, the first and second aspects A1 and A2 are used for each permanent magnet 23 and each outer core portion 25 corresponding to each magnet housing hole 24, and each magnetic pole portion 26 as well. There are eight magnetic pole boundary lines Ld between adjacent magnetic pole portions 26 at equal intervals in the circumferential direction. The magnetic pole opening angle θm of the magnetic pole portion 26 between the adjacent magnetic pole boundary lines Ld is 45°. The circumferential centerline of the adjacent magnetic pole boundary lines Ld is the magnetic pole centerline Ls of each magnetic pole portion 26 . Each magnetic pole portion 26 having substantially the same configuration has a substantially line-symmetrical configuration about the magnetic pole center line Ls.

Each outer core portion 25 has three apex portions connected to the peripheral portion of the rotor core 22 at connecting portions called bridge portions. A radial inner vertex portion of each outer core portion 25 is supported by a reinforcing bridge portion 22c. The reinforcing bridge portion 22c is a bridge portion that crosses the bent portion 24b of the magnet housing hole 24 in the hole width direction, in this case, the radial direction of the rotor core 22 . Two vertex portions on the radially outer side of each outer core portion 25 are supported by outer

peripheral bridge portions

22d and 22e, respectively. The outer

peripheral bridge portions

22 d and 22 e extend in the circumferential direction of the rotor core 22 from the radial outer end portion 24 c of the straight portion 24 a of the magnet housing hole 24 .

Interpolar bridge portions 22f are provided between the adjacent magnet housing holes 24. As shown in FIG. The interpolar bridge portion 22f is a bridge portion extending radially between the straight portions 24a of the adjacent magnet housing holes 24. As shown in FIG. The interpolar bridge portion 22f, the reinforcing bridge portion 22c, and the outer

peripheral bridge portions

22d and 22e are provided for each axially laminated core sheet 30 corresponding to the magnet housing holes 24 of the first and second aspects A1 and A2. It is configured so that it is alternately absent (see FIGS. 4 to 6). Further, the interpolar bridge portion 22f, the reinforcing bridge portion 22c, and the outer

peripheral bridge portions

22d, 22e are reversed in order of presence/absence for each of the magnet housing holes 24 of the first and second aspects A1, A2. A detailed configuration will be described later.

The permanent magnets 23 embedded in the magnet housing holes 24 of the rotor core 22 are magnetized from the outside of the rotor core 22 using a magnetizing device (not shown) after the magnet material before being magnetized is solidified. . In this case, each permanent magnet 23 is magnetized in its thickness direction. The linear portion 24a is magnetized in the direction orthogonal to the radial direction in which it extends, and the curved portion 24b is magnetized in the radial direction. The permanent magnets 23 of each magnetic pole portion 26 are magnetized so as to alternately have different polarities in the circumferential direction. Thus, each magnetic pole portion 26 is configured to obtain both magnet torque by the permanent magnet 23 and reluctance torque by the outer core portion 25 .

[Core sheet 30]
The rotor core 22 is constructed by laminating a plurality of core sheets 30 made of electromagnetic steel sheets in the direction of the axis L. As shown in FIG. As for the individual core sheets 30, those having the same configuration as shown in FIG. 3(a) are used. Since each core sheet 30 uses the same parts, it is easy to manage. Although the core sheet 30 shown in FIG. 3(b) appears to have a different shape from the core sheet 30 shown in FIG. It is arranged at the second position rotated by 45°, which is the magnetic pole portion.

In one core sheet 30, a first magnet through hole 31 and a second magnet through hole 32 are mixedly formed as two types of magnet through holes having different shapes. The first and second magnet through

holes

31 and 32 are alternately provided in each core sheet 30 in the circumferential direction. Each of the first and second magnet through

holes

31 and 32 is provided alternately in the circumferential direction. The first and second magnet through-

holes

31 and 32 each have a substantially V-shaped folded shape that protrudes radially inward. That is, the first magnet through-hole 31 has a shape in which the radially inner ends of the pair of linear portions 31a are connected to each other by the bent portion 31b. The second magnet through-hole 32 has a shape in which the radially inner ends of the pair of linear portions 32a are connected to each other by a bent portion 32b.

The first magnet through hole 31 is provided at a position where its own hole center line L1 is offset from the magnetic pole center line Ls of each magnetic pole portion 26 in the counterclockwise direction in FIG. 3(a). On the other hand, the second magnet through-hole 32 is provided at a position where its own hole center line L2 is offset from the magnetic pole center line Ls of each magnetic pole portion 26 in the clockwise direction in FIG. 3(a). As a result, the

linear portions

31a and 32a of the first magnet through-hole 31 and the second magnet through-hole 32 adjacent thereto in the clockwise direction are separated from each other. The first magnet through-hole 31 and the second magnet through-hole 32 adjacent thereto in the clockwise direction have individual interpolar bridge pieces 33 that constitute the interpolar bridge portion 22f. On the other hand, the

straight portions

31a and 32a of the first magnet through-hole 31 and the second magnet through-hole 32 adjacent in the counterclockwise direction are coupled to each other. The first magnet through-hole 31 and the second magnet through-hole 32 adjacent thereto in the counterclockwise direction do not have the individual interpolar bridge pieces 33 constituting the interpolar bridge portion 22f. In this embodiment, since the

straight portions

31a and 32a are joined at the magnetic pole boundary line Ld, the widths of the

straight portions

31a and 32a themselves are not reduced.

Further, the portions where the

straight portions

31a and 32a of the first and second magnet through

holes

31 and 32 are spaced apart from each other, that is, the portions where the interpolar bridge pieces 33 are located are individual outer peripheral bridges constituting the outer

peripheral bridge portions

22d and 22e. It has a mode with

pieces

31c and 32c. Since the interpolar bridge piece 33 and the outer

peripheral bridge pieces

31c and 32c are connected to each other, they have a rational relationship of supporting each other. On the other hand, the portions where the

straight portions

31a and 32a of the first and second magnet through-

holes

31 and 32 are coupled do not have the outer

peripheral bridge pieces

31c and 32c that constitute the outer

peripheral bridge portions

22d and 22e. there is Further, the curved portion 31b of the first magnet through-hole 31 has individual reinforcing bridge pieces 31d that constitute the reinforcing bridge portion 22c. On the other hand, the bent portion 32b of the through-hole 32 for the second magnet does not have the individual reinforcing bridge pieces 31d that constitute the reinforcing bridge portion 22c.

That is, each outer core portion 34a provided so as to be surrounded by the first magnet through hole 31 to constitute the outer core portion 25 includes a reinforcing bridge piece 31d and an outer peripheral bridge piece at a portion where the interpolar bridge piece 33 is present. 31c is supported at two points. On the other hand, the individual outer core portions 34b provided so as to be surrounded by the second magnet through holes 32 to constitute the outer core portion 25 are provided only at one location on the outer peripheral bridge piece 32c where the interpolar bridge piece 33 is located. This is the supported mode. In the individual core sheets 30, the supporting stiffness of the individual

outer core portions

34a, 34b is not very high. However, in the rotor core 22 of this embodiment, the core sheet 30 arranged at the first position shown in FIG. 3A and the core sheet arranged at the second position shown in FIG. (so-called transduction). The outer core portion 25 of the rotor core 22 produced by rolling the core sheets 30 is supported at a total of three points, that is, the reinforcing bridge portion 22c and the two outer

peripheral bridge portions

22d and 22e. The support stiffness of is increased.

In addition, in the first magnet through-hole 31, a tapered portion is provided at the inner corner of the V-shaped folded shape at the radially outer end of the linear portion 31a positioned counterclockwise from the magnetic pole center line Ls. 31e is provided. In the first magnet through-hole 31, a tapered portion 31f is provided at an inner corner portion of the V-shaped folded shape at the radially outer end portion of the linear portion 31a that is shifted clockwise from the magnetic pole center line Ls. It is In the second magnet through-hole 32, a tapered portion is provided at the inner corner of the V-shaped folded portion at the radially outer end of the linear portion 32a positioned counterclockwise from the magnetic pole center line Ls. 32d is provided. In the second magnet through-hole 32, a tapered portion 32e is provided at the inner corner of the V-shaped folded portion at the radially outer end portion of the linear portion 32a that is shifted clockwise from the magnetic pole center line Ls. It is The inner edges of the

tapered portions

31e, 31f, 32d, and 32e project obliquely inward. Each of the

tapered portions

31e and 32e is set to have a protrusion amount larger than that of each of the

tapered portions

31f and 32d.

[Fabrication of rotor core 22 and rotor 20 by stacking core sheets 30]
In manufacturing the rotor 20 including the rotor core 22, in the present embodiment, the core sheet 30 is placed one by one at the first position shown in FIG. are alternately stacked in the axial direction with those arranged at the second position shown in FIG. As a result, the first magnet through-holes 31 and the second magnet through-holes 32 are alternately overlapped in the axial direction, and the magnets of the rotor core 22 are separated by the axially overlapping first and second magnet through-

holes

31 and 32 . A receiving hole 24 is formed.

In the axial view shown in FIG. 2, the first magnet through-holes 31 appearing in the axial end face of the rotor core 22 are the magnet housing holes 24 of the first aspect A1 and the magnetic pole portions 26 of the first aspect A1. In the magnet housing hole 24 of the first mode A1, the first sheet of the core sheet 30 is the through hole 31 for the first magnet, and the second sheet of the core sheet 30 is the through hole 32 for the second magnet. That is, the odd-numbered core sheets 30 are configured with the first magnet through-holes 31 and the even-numbered core sheets 30 are configured with the second magnet through-holes 32 . Similarly, when viewed in the axial direction, the second magnet through holes 32 appearing in the axial end face of the rotor core 22 are the magnet containing holes 24 of the second mode A2 and the magnetic pole portions 26 of the second mode A2. In the magnet housing hole 24 of the second mode A2, the first sheet of the core sheet 30 is the through hole 32 for the second magnet, and the second sheet of the core sheet 30 is the through hole 31 for the first magnet. That is, the odd-numbered core sheets 30 are configured with the second magnet through-holes 32 and the even-numbered core sheets 30 are configured with the first magnet through-holes 31 .

In this case, the first magnet through hole 31 is offset counterclockwise from the magnetic pole center line Ls of each magnetic pole portion 26, and the second magnet through hole 32 is offset clockwise from the magnetic pole center line Ls. are doing. That is, each magnet housing hole 24 of the first and second aspects A1 and A2 has a zigzag shape in the axial direction. The inner surface of each magnet housing hole 24 is configured to have an uneven shape. Therefore, the permanent magnets 23 manufactured by injection molding into the magnet housing holes 24 partially enter into the concave and convex portions of the inner surfaces of the magnet housing holes 24, so that the permanent magnets 23 are strongly connected to each other. .

If the number of core sheets 30 to be laminated is an even number, the same number of first and second magnet through

holes

31 and 32 are formed in each magnet housing hole in both the first and second modes A1 and A2. 24 will be configured. Therefore, even if the shape of each magnet housing hole 24 appearing on the axial end surface of the rotor core 22 is different in the first and second aspects A1 and A2, the magnetic pole portions 26 in the first and second aspects A1 and A2 are They have substantially the same configuration. The rotor core 22 of this embodiment is composed of, for example, an even number of core sheets 30 .

As for fixing the plurality of core sheets 30, for example, the core sheets 30 adjacent to each other in the stacking direction are fixed using an adhesive (not shown). As another example, adjacent core sheets 30 may be fixed using a crimping portion 35 (see FIG. 2). The caulking portion 35 is formed by, for example, forming a recess on the front side of the core sheet 30 and a protrusion on the back side of the core sheet 30, and fitting and crimping the protrusions and recesses in the stacking direction. One preferable example of the positions at which the crimped portions 35 are provided is to set one crimped portion 35 near the center of each outer core portion 25 on the magnetic pole center line Ls of each magnetic pole portion 26 . The arrangement, number, etc. of the crimped portions 35 are not limited to this, and may be changed as appropriate.

[Action of this embodiment]
The operation of this embodiment will be described.
In the rotor 20 shown in FIG. 2, the outer core portion 25 of each magnetic pole portion 26 is supported at a total of three locations, one reinforcing bridge portion 22c and two outer

peripheral bridge portions

22d and 22e. there is On the other hand, in each core sheet 30 shown in FIG. 3(a), each outer core portion 34a surrounded by the first magnet through-holes 31 consists of a reinforcing bridge piece 31d and an outer peripheral bridge piece 31c. It is support in places. Each outer core portion 34b surrounded by the second magnet through-holes 32 is supported only at one position on the outer peripheral bridge piece 32c. By producing the rotor core 22 by rolling a plurality of core sheets 30, the outer core portion 25 is supported at a total of three points: the reinforcing bridge portion 22c and the two outer

peripheral bridge portions

22d and 22e. The support rigidity of the outer core portion 25 in the finished state of the rotor core 22 is high, and the centrifugal force strength of the rotor core 22, that is, the rotor 20 is sufficient. In addition, the reinforcing bridge portion 22c and the outer

peripheral bridge portions

22d and 22e shown in FIGS. Existence and nonexistence. In other words, the reinforcing bridge portion 22c and the outer

peripheral bridge portions

22d and 22e are appropriately thinned out in the axial direction. Therefore, it is possible to reduce leakage magnetic flux, which is a concern in the reinforcing bridge portion 22c and the outer

peripheral bridge portions

22d and 22e. In other words, the rotor 20 of the present embodiment is configured to ensure both the strength of the centrifugal force and the reduction of leakage magnetic flux.

Also, as shown in FIG. 2, each magnet housing hole 24 has a configuration in which the first and second magnet through

holes

31 and 32 are mixed in the axial direction in consideration of the rotation of the rotor core 22 . That is, since each magnet housing hole 24 has a zigzag shape in the axial direction, and the inner surface thereof is uneven, each permanent magnet 23 enters the uneven portion of the inner surface of each magnet housing hole 24 during the molding stage. Therefore, the connection between each permanent magnet 23 and the rotor core 22 becomes strong. This also contributes to increasing the rigidity of the rotor 20 as a whole. Since the

tapered portions

31e, 31f, 32d, and 32e of the first and second magnet through

holes

31 and 32 also have different protruding amounts, the corresponding V-shaped folded shape of the permanent magnets 23 is formed. The tapered portion 23c at the inner corner of the shaft also has an uneven shape in the axial direction. Also in this portion, the connection between each permanent magnet 23 and the rotor core 22 becomes strong. Further, since the reinforcing bridge portion 22c, the outer

peripheral bridge portions

22d and 22e, and the interpolar bridge portion 22f shown in FIGS. 23 enters. Therefore, the connection between each permanent magnet 23 and the rotor core 22 is strong at this portion as well. This also contributes to improving the rigidity of the rotor 20 as a whole.

In addition, the results of various comparative studies on the shape and arrangement of the permanent magnets 23 of the rotor 20 are shown below.
First, the results of comparative examination of the total widths W1 and W2 of the linear portions 23a of the permanent magnets 23 of the adjacent poles will be shown. The total width W1 is the sum of the linear portions 23a that connect the adjacent poles of the portion without the inter-electrode bridge portion 22f (or the inter-electrode bridge piece 33). The total width W2 is the sum of the straight portions 23a of adjacent poles including the width of the portion where the interpolar bridge portion 22f (or the interpolar bridge piece 33) is present. FIG. 7 shows the configuration of the present proposal. The linear portions 23a of the permanent magnets 23 having the same polarity are set to have the same width. The total width W2 is greater than the total width W1 (W1<W2) due to the presence of the inter-electrode bridge portion 22f. On the other hand, FIG. 8 shows the configuration of Comparative Example 1, and FIG. 9 shows the configuration of Comparative Example 2. As shown in FIG. In Comparative Examples 1 and 2, the width of the linear portion 23a at the portion where the inter-electrode bridge portion 22f is provided is narrowed. In Comparative Example 1, the total width W2 and the total width W1 are set to be the same (W1=W2). Comparative Example 2 is set such that the total width W1 is larger than the total width W2 (W1>W2).

FIG. 10 shows torque fluctuations of the rotating electric machine M. FIG. 10 shows the magnitude of the cogging torque when no current is supplied. It can be seen that the cogging torque of the rotary electric machine M is most suppressed in the present invention in which the total widths W1 and W2 are set to "W1<W2". On the other hand, in Comparative Example 2 in which the total widths W1 and W2 are set to "W1>W2", the cogging torque is slightly increased as compared with the present invention. In Comparative Example 1 in which the total widths W1 and W2 were set to "W1=W2", the cogging torque was slightly increased compared to Comparative Example 2.

FIG. 11 also shows the torque fluctuations of the rotating electric machine M. FIG. 11 shows the magnitude of the torque ripple during energization. It can be seen that in the present invention in which the total widths W1 and W2 are set to "W1<W2", a large torque is obtained in the rotary electric machine M and the torque ripple is sufficiently suppressed. On the other hand, in Comparative Example 1 in which the total widths W1 and W2 are set to "W1=W2", a slightly larger torque than the present invention is obtained, but the torque ripple is slightly increased. Further, in Comparative Example 2 in which the total widths W1 and W2 are set to "W1>W2", the torque is slightly decreased and the torque ripple is slightly increased as compared with the present invention. Since the results of both Comparative Examples 1 and 2 are sufficiently acceptable, the settings of Comparative Examples 1 and 2 may be adopted.

Next, various comparisons were made on the presence and shape of the

tapered portions

31e, 31f, 32d, and 32e of the first and second magnet through

holes

31 and 32 constituting each magnet housing hole 24. In other words, various comparisons and examinations were made on the presence and shape of the tapered portions 23c at the corners of the permanent magnets 23. FIG.

FIG. 12 shows the torque ripple rate of the rotating electric machine M. In the present proposal in which the tapered portions 23c are provided at the corners of the permanent magnets 23, the ripple rate is suppressed as compared with the comparative example (not shown) in which the tapered portions are not provided. Since the comparative example without the tapered portion is also sufficiently acceptable, a configuration without the tapered portion may be employed.

FIG. 13 also shows the torque ripple rate of the rotating electric machine M. This is the result of comparison and examination as to whether the sizes of the tapered portions 23c provided at the corners of the permanent magnets 23 (referred to as taper amounts in FIG. 13) are the same or different in the axial direction. In the present invention, in which the sizes of the tapered portions 23c provided at the corners of the permanent magnets 23 are different in the axial direction, ripples are less than in the comparative example (not shown) in which the sizes of the tapered portions are the same in the axial direction. rate is reduced. A comparative example in which the size of the tapered portion is the same in the axial direction is also sufficiently acceptable, so a configuration in which the size of the tapered portion is the same in the axial direction may be adopted.

[Effect of this embodiment]
Effects of the present embodiment will be described.
(1) The outer core portion 25 surrounded by the magnet housing hole 24 and the permanent magnets 23 is supported with respect to the peripheral portion of the rotor core 22 by three support modes of the pair of outer

peripheral bridge portions

22d and 22e and the reinforcing bridge portion 22c. Supported. In each core sheet 30, in forming one outer core portion 25, only one outer core portion 34a supported by two outer peripheral bridge pieces 31c and reinforcing bridge pieces 31d and one outer peripheral bridge piece 32c are used. It is intermingled with the supported outer core portion 34b. When the rotor core 22 is produced by stacking a plurality of core sheets 30, the outer core portion 25 is supported by the outer

peripheral bridge portions

22d and 22e and the reinforcing bridge portion 22c. . Since the support rigidity of the outer core portion 25 supported by the

bridge portions

22d, 22e, and 22c at a plurality of locations is sufficiently high, the strength of the centrifugal force of the rotor 20 can be ensured. On the other hand, by mixing the outer core portion 34b and the like supported by one outer peripheral bridge piece 32c, the

individual bridge pieces

31c, 22d, 22e, and 22c that support the outer core portion 25 are formed. 32c and 31d are moderately thinned out. Therefore, it is possible to reduce leakage magnetic flux that is a concern in each of the

bridge portions

22d, 22e, and 22c.

The outer peripheral bridge portion 22d and the outer peripheral bridge portion 22e correspond to the first bridge portion and the second bridge portion. The reinforcing bridge portion 22c corresponds to a third bridge portion. The peripheral bridge piece 31c and the peripheral bridge piece 32c correspond to the first bridge piece and the second bridge piece. The reinforcing bridge piece 31d corresponds to a third bridge piece.

(2) In the core sheet 30, the first magnet through holes 31 having the outer peripheral bridge pieces 31c and the reinforcing bridge pieces 31d and the second magnet through holes 32 having the outer peripheral bridge pieces 32c are alternately arranged in the circumferential direction. are provided in a mixed manner on one sheet. The rotor core 22 rotates the core sheet 30 so that each predetermined number of core sheets 30 (in this embodiment, each sheet) has a magnet containing hole 24 in which the first and second magnet through

holes

31 and 32 are mixed. It is a laminated structure. That is, since the rotor core 22 of the present embodiment can be configured with one type of core sheet 30, it can be realized with a simple response.

(3) The rotor core 22 is laminated by rotating the same number of core sheets 30, in this embodiment, one sheet at a time. As a result, improvement in rotational balance of the rotor 20 using the rotor core 22 can be expected.

(4) The rotor core 22 has inter-polar bridge portions 22 f between the magnet housing holes 24 of the adjacent magnetic pole portions 26 . The core sheet 30 has interpolar bridge pieces 33 between the adjacent first and second magnet through

holes

31 and 32 on one side, and eliminates the interpolar bridge pieces 33 on the adjacent other side to form the first and second magnet through

holes

31 and 32 . The two magnet through

holes

31 and 32 are connected to each other. In such a configuration, the outer

peripheral bridge pieces

31c and 32c are provided only at a portion where the inter-electrode bridge piece 33 is present. In other words, the interpolar bridge piece 33 and the outer

peripheral bridge pieces

31c and 32c are connected to each other and support each other, so this is a rational configuration.

Note that the inter-electrode bridge portion 22f corresponds to a fourth bridge portion. The inter-electrode bridge piece 33 corresponds to a fourth bridge piece.
(5) The total width W1 of the linear portions 23a of the adjacent permanent magnets 23 that are coupled to each other at the portion without the interpolar bridge portion 22f, and the total width W1 of the linear portion 23a including the interpolar bridge portion 22f at the portion with the interpolar bridge portion 22f. It is set to be different from the total width W2. Especially in this embodiment, the total width W2 is set to be larger than the total width W1. The effect of sufficiently suppressing both the cogging torque and torque ripple of the rotary electric machine M can be expected.

The linear portion 23a of the adjacent permanent magnets 23 corresponds to the side-by-side portion of the adjacent permanent magnets. The total width W1 corresponds to the first total width. The total width W2 corresponds to the second total width.
(6) The permanent magnet 23 is provided with a tapered portion 23c at the corner of the outer peripheral side end of the rotor core 22 . Especially in this embodiment, the sizes of the tapered portions 23c provided at the respective corners of the pair of linear portions 23a are set to be different from each other. With this as well, the effect of sufficiently suppressing the torque ripple of the rotary electric machine M can be expected.

(7) The first magnet through-hole 31 is arranged at a position offset to one side in the circumferential direction with respect to the magnetic pole center line Ls of the magnetic pole portion 26, and the second magnet through-hole 32 is arranged with respect to the magnetic pole center line Ls. is offset to the other side in the circumferential direction. The first and second magnet through-

holes

31 and 32 are formed in a V-shaped folded shape asymmetrically with respect to the magnetic pole center line Ls. The magnet housing hole 24 is configured such that the first and second magnet through-

holes

31 and 32 are intermingled, so that the inner surface thereof is uneven. Therefore, the permanent magnets 23 manufactured by injection molding into the magnet housing holes 24 as in the present embodiment partly enter into the irregularities on the inner surface of the magnet housing holes 24, so that they are strongly coupled to each other. Become. The stronger coupling between the permanent magnets 23 and the rotor core 22 contributes to an improvement in the rigidity of the rotor 20 as a whole.

[Change example]
This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

- The various comparative examples described above are also modified examples, and may be modified as appropriate. Also, the above-described embodiment and various comparative examples may be combined as appropriate.
- The shape of the magnet housing hole 24 and the first and second magnet through

holes

31 and 32 is an example, and may be changed as appropriate. In this case, the shape of the permanent magnet 23 produced by injection molding into the magnet housing hole 24 is also changed.

Incidentally, in the above embodiment, the main shape of the permanent magnets 23 of the adjacent magnetic pole portions 26 is configured symmetrically with respect to the magnetic pole boundary line Ld. The main shape of the permanent magnet 23 is an approximate shape excluding the portions related to the

bridge portions

22c, 22d, and 22e of the magnet housing hole 24 and the tapered portions 23c. As shown in FIG. 14, the main shape of the permanent magnets 23 of the adjacent magnetic pole portions 26 may be varied to be asymmetric with respect to the magnetic pole boundary line Ld. In FIG. 14, as an example, the widths of the pair of linear portions 23a in the permanent magnet 23 of the magnetic pole portion 26 of the second mode A2 are set to the same width W3. The widths of the linear portions 23a of the permanent magnets 23 of the magnetic pole portions 26 of the first mode A1 are set to different widths W4 and W5. This is an example in which the width of the permanent magnet 23 is changed as a main change in the shape of the permanent magnet 23 .

15 and 16 show the cogging torque and torque ripple rate of the rotating electric machine M, respectively. Compared to the above-described embodiment in which the main shape of the permanent magnet 23 of the adjacent magnetic pole portion 26 is symmetrical with respect to the magnetic pole boundary line Ld, the modification shown in FIG. is suppressed. Since the cogging torque and the ripple rate are sufficiently permissible even with symmetry, the symmetric mode is adopted in the above-described embodiment. An asymmetrical aspect can also be adopted as in the modified example.

- One outer core portion 25 is supported at three locations, that is, the outer

peripheral bridge portions

22d and 22e and the reinforcing bridge portion 22c, but one of these is omitted at two locations, or another bridge portion is added at four locations. It is good also as a support mode of the above multiple places. In addition, the shape, arrangement, presence/absence, and combination of the outer

peripheral bridge portions

22d and 22e, the reinforcing bridge portion 22c and the interpolar bridge portion 22f, and the individual outer

peripheral bridge pieces

31c and 32c, the reinforcing bridge piece 31d and the interpolar bridge piece 33, respectively. etc., may be changed as appropriate.

· Although the rotor core 22 is configured such that the core sheets 30 are rotated one by one to be laminated, the core sheets 30 may be rotated and laminated by a predetermined number of sheets of two or more. In this case, it may be every same number of sheets or every different number of sheets.

· Although the rotor core 22 has a configuration in which a plurality of core sheets 30 of one type are laminated, it may have a configuration in which a plurality of types of core sheets (not shown) are laminated. In this case, the core sheets may be laminated while being rotated, or may be laminated without being rotated.

The curvature of the outer peripheral surface 26a of each magnetic pole portion 26 is made larger than the curvature when the outer peripheral surface 22a of the rotor core 22 is a uniform circumference, and the outer peripheral surface 22a of the rotor core 22 is configured in a wavy shape. may be, for example, a generally uniform circumference.

·Although the permanent magnets 23 are produced by filling the magnet housing holes 24 with the magnet material that will become the permanent magnets 23, the permanent magnets 23 that have been produced in advance may be inserted into the magnet housing holes 24.

- The number of magnetic poles of the rotor 20, that is, the number of the permanent magnets 23 and the magnet housing holes 24 may be changed as appropriate. Also, the number of magnetic poles of the stator 10 may be changed as appropriate.
- In addition to the above, the configuration of the rotary electric machine M may be changed as appropriate.

- The statement "at least one of A and B" in this specification should be understood to mean "only A, or only B, or both A and B."
- Although the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to such examples or structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and configurations, as well as other combinations and configurations, including single elements, more, or less, are within the scope and spirit of this disclosure.

Claims

a rotor core (22) including a plurality of laminated core sheets (30) and having a magnet accommodation hole (24) having a folded shape convex radially inward;
A rotor (20) comprising permanent magnets (23) embedded in magnet housing holes of the rotor core,
the rotor includes a plurality of magnetic pole pieces (26);
Each of the plurality of magnetic pole portions includes the permanent magnet located radially inside the rotor core, and an outer core portion (25) that is a portion of the rotor core located radially outside the permanent magnet. and
The outer core portion of the rotor core is formed by laminating the outer core portions (34a, 34b) of the individual core sheets, and a pair of radially outer end portions (24c) of the folded magnet accommodating holes are formed. The rotor core is supported by a plurality of bridge portions (22d, 22e, 22c) including bridge portions located on at least one side of the rotor core,
At least the outer core portion (34b) supported by one bridge piece (32c) of the core sheet forming the bridge portion (22e) of the one radially outer end is mixed, and a plurality of The rotor is configured such that the outer core portion is supported by the plurality of bridge portions by stacking the core sheets.
The outer core portion of the rotor core includes first and second bridge portions (22d, 22e) respectively provided at a pair of radially outer end portions of the magnet accommodation holes having the folded shape, and midway positions of the magnet accommodation holes. is supported with respect to the peripheral portion of the rotor core at at least three points including the third bridge portion (22c) provided so as to cross the hole in the
each of the outer core portions supported by one or two of the first to third bridge pieces (31c, 32c, 31d) of the core sheet constituting the first to third bridge portions; A plurality of the core sheets are mixed so that a plurality of the core sheets are laminated so that the outer core portion is supported by at least three portions of the first to third bridge portions. 1. The rotor according to claim 1.
The core sheet includes a first magnet through hole (31) having two bridge pieces (31c, 31d) out of the first to third bridge pieces, and a remaining one hole not in the first magnet through hole (31). second magnet through-holes (32) having bridge pieces (32c) are arranged alternately in the circumferential direction and provided in one sheet,
The rotor core uses a plurality of core sheets having the same configuration, and the core sheets are rotated so that each predetermined number of core sheets has a magnet containing hole in which the through holes for the first and second magnets are mixed. 3. A rotor according to claim 2, wherein the rotor is laminated with
The rotor according to claim 3, wherein the rotor core is laminated by rotating the same number of core sheets.
The rotor core has a fourth bridge portion (22f) between the magnet housing holes of the adjacent magnetic pole portions,
The core sheet has a fourth bridge piece (33) for forming the fourth bridge portion between the first and second magnet through holes on one side, and the fourth bridge piece (33) on the other side. The fourth bridge piece is removed between the first and second magnet through-holes, and the first and second magnet through-holes are connected to each other,
5. The rotor according to claim 3, wherein said first and second bridge pieces are provided only at a portion where said fourth bridge piece is provided.
With respect to the total width (W1, W2) of the adjacent juxtaposed portions (23a) of the adjacent permanent magnets, the first total width (W1) of the juxtaposed portions coupled to each other at the portion without the fourth bridge portion 6. The rotor according to claim 5, wherein the second total width (W2) of the juxtaposed portion including the fourth bridge portion is set to be different at the portion where the fourth bridge portion is present.
The rotor according to claim 6, wherein the second total width of the portion with the fourth bridge portion is set to be larger than the first total width of the portion without the fourth bridge portion.
The first magnet through-hole is arranged at a position offset to one side in the circumferential direction with respect to the magnetic pole center line (Ls) of the magnetic pole portion, and the second magnet through-hole is arranged with respect to the magnetic pole center line. arranged at a position offset to the other side in the circumferential direction, and the folded shapes of the first and second magnet through holes are configured asymmetrically with respect to the magnetic pole center line,
8. The rotor according to any one of claims 3 to 7, wherein the magnet containing hole has an uneven inner surface due to a mixture of the first and second magnet through holes.
The rotor according to any one of claims 1 to 8, wherein said permanent magnets are provided with tapered portions (23c) at the corners of the outer peripheral side end of said rotor core.
10. The permanent magnets are provided with tapered portions (23c) at respective corners of the outer peripheral side end portions of the folded rotor core, and are set to have different sizes. rotor described in .
The rotor according to any one of claims 1 to 10, wherein the permanent magnet has its main shape asymmetrical with respect to the magnetic pole boundary line (Ld) of the adjacent magnetic pole portion.
A rotor core (22) including a plurality of laminated core sheets (30) and having a magnet housing hole (24) with a radially inwardly convex folded shape; permanent magnets embedded in the magnet housing holes of the rotor core ( 23), a rotor (20) comprising
a stator (10) for applying a rotating magnetic field to the rotor;
A rotating electrical machine (M) comprising
The rotor of the rotating electric machine includes a plurality of magnetic pole portions (26),
Each of the plurality of magnetic pole portions (26) includes the permanent magnet positioned radially inside the rotor core, and an outer core portion (25) which is a part of the rotor core positioned radially outside the permanent magnet. contains
The outer core portion of the rotor core is formed by laminating the outer core portions (34a, 34b) of the individual core sheets, and a pair of radially outer end portions (24c) of the folded magnet accommodating holes are formed. The rotor core is supported by a plurality of bridge portions (22d, 22e, 22c) including bridge portions located on at least one side of the rotor core,
At least the outer core portion (34b) supported by one bridge piece (32c) of the core sheet forming the bridge portion (22e) of the one radially outer end is mixed, and a plurality of A rotary electric machine, wherein the outer core portion is supported by the plurality of bridge portions by stacking the core sheets.